Completely replace soil? Or mix in fertilizer and reuse
 

Ramping up to plant this year and realized I'm unsure of how to transition last years containers to begin this years garden. Backstory: last year was my first year container gardening as I've always had a yard. I had a very successful season with a rooftop garden of 25+ containers ranging from 10 gallon -25 gallon. At the end of the season I pulled all plants from the containers, roots and all. Now I am left with containers of dirt. Do I need to trash the soil left behind and start completely over with all new mix? Or could I reuse the dirt with addition of compost, fish meal or other additives?
I'd like to avoid hauling huge amounts of dirt down through a condo building but on the flip side don't want to be lazy and risk jeopardizing this years garden.

Thoughts?

Duplicate post. Mods please delete